A sportsbook is a gambling establishment, whether it’s a website or brick-and-mortar building, that accepts bets on sports events. It’s also sometimes referred to as a bookmaker or “bookie.” A sportsbook has the same purpose as any other type of gambling establishment, to make a profit over time by accepting bets and paying winners.

Many states only recently made sportsbooks legal, allowing people to place wagers on a variety of different sports. This was a big step forward for sports betting, and it has paved the way for new concepts like fantasy sports and esports. It’s important to remember that gambling always involves a negative expected return, and you should always gamble responsibly.

In the world of sports betting, everything revolves around odds. These odds are a representation of the probability of an outcome expressed as a price, and they’re used by sportsbooks to calculate bets. Most sportsbooks use American odds, which show how much you could win with a $100 bet and use positive (+) or negative (-) odds to indicate how much money you would need to risk in order to make a profit.

Another way that a sportsbook makes money is by charging a commission, known as the vig, on losing bets. This is standard in most industries, and it’s typically between 100% and 110% of the amount of the bet. This helps sportsbooks stay profitable over the long run and ensures that their customers are treated fairly.